Zoom lens and imaging apparatus

ABSTRACT

A zoom lens includes, in order from the object side, a first lens group having a negative refractive power, a second lens group having a positive refractive power and a third lens group having a positive refractive power, wherein, during magnification change from the wide-angle end to the telephoto end, at least the first lens group and the second lens group are moved along the optical axis such that the interval between the first lens group and the second lens group is decreased and the interval between the second lens group and the third lens group is increased. The second lens group includes, in order from the object side, a positive lens, a cemented lens formed by a positive lens and a negative lens, a positive lens and a negative lens. The zoom lens satisfies given conditional expressions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2012/007823 filed on Dec. 6, 2012, which claims priority under 35U.S.C §119 (a) to Japanese Patent Application No. 2011-269674 filed onDec. 9, 2011. Each of the above applications is hereby expresslyincorporated by reference, in its entirety, into the presentapplication.

TECHNICAL FIELD

The present invention relates to a zoom lens and an imaging apparatus,and more particularly to a zoom lens that is suitable for use with adigital camera, a video camera, etc., and an imaging apparatus providedwith the zoom lens.

BACKGROUND ART

In recent years, along with the spread of personal computers in ordinaryhomes, digital cameras that are capable of inputting image information,such as photographed landscapes and portraits, to a personal computerare also widely spreading. Further, recent digital cameras are more andmore sophisticated, and there are demands for a digital camera equippedwith a zoom lens that allows successful wide-angle imaging.

In order to meet such demands, a zoom lens, such as zoom lensesdisclosed in Japanese Unexamined Patent Publication Nos. 2003-107348 and2009-156905 (hereinafter, Patent Documents 1 and 2), for example, whichconsists of, in order from the object side, a first lens group having anegative refractive power, a second lens group having a positiverefractive power and a third lens group having a positive refractivepower, where magnification change is achieved by changing an intervalbetween the groups, is used. Further, Japanese Unexamined PatentPublication No. 2011-081185 (hereinafter, Patent Document 3) discloses azoom lens that has a similar basic configuration to those of PatentDocuments 1 and 2 and has a small F-number at the wide-angle end.

DISCLOSURE OF INVENTION

In recent years, however, there are increasing demands for a zoom lensthat is a wide angle lens and is capable of achieving a small F-numberand reduction of the entire length of the zoom lens. The zoom lensesdisclosed in Patent Documents 1 and 2 have a large F-number at thewide-angle end, and therefore a lens having a smaller F-number isdemanded. The zoom lens disclosed in Patent Document 3 has a large ratioof the entire length of the lens to the image size, and thereforereduction of the entire length of the lens is demanded.

In view of the above-described circumstances, the present invention isdirected to providing a zoom lens that is a wide-angle lens and has highoptical performance for achieving a small F-number and reduction of theentire length of the zoom lens, and an imaging apparatus provided withthe zoom lens.

The zoom lens of the invention substantially consists of three lensgroups including, in order from an object side, a first lens grouphaving a negative refractive power, a second lens group having apositive refractive power and a third lens group having a positiverefractive power, wherein, during magnification change from a wide-angleend to a telephoto end, at least the first lens group and the secondlens group are moved along an optical axis such that an interval betweenthe first lens group and the second lens group is decreased and aninterval between the second lens group and the third lens group isincreased, the second lens group consists of, in order from the objectside, a second-group first lens having a positive refractive power, acemented lens consisting of a second-group second lens having a positiverefractive power and a second-group third lens having a negativerefractive power, a second-group fourth lens having a positiverefractive power, and a second-group fifth lens having a negativerefractive power, and the conditional expressions (1) and (2) below aresatisfied:

−0.9<fw/f25<0  (1), and

−0.40<(R15+R16)/(R15−R16)<2.40  (2),

where fw is a focal length of the entire lens system at the wide-angleend, f25 is a focal length of the second-group fifth lens, R15 is aparaxial radius of curvature of an object-side surface of thesecond-group fifth lens, and R16 is a paraxial radius of curvature of animage-side surface of the second-group fifth lens.

It should be noted that, in the invention, the “lens group” as usedherein refers not only a lens group formed by a plurality of lenses butalso a lens group formed by only one lens.

It should be noted that the expression “substantially consists(consisting) of three lens groups” as used herein means that the zoomlens of the invention may include: a lens substantially without anypower; optical elements other than lenses, such as a stop and a glasscover; and mechanical components, such as a lens flange, a lens barrel,an image sensor, and a camera shake correcting mechanism; in addition tothe three lens groups.

It is more preferable that the zoom lens of this embodiment satisfiesthe conditional expressions (1-1) and (2-1) below:

−0.78<fw/f25<−0.14  (1-1), and

−0.35<(R15+R16)/(R15−R16)<0.30  (2-1)

where fw is a focal length of the entire lens system at the wide-angleend, f25 is a focal length of the second-group fifth lens, R15 is aparaxial radius of curvature of the object-side surface of thesecond-group fifth lens, and R16 is a paraxial radius of curvature ofthe image-side surface of the second-group fifth lens.

It is preferable that the zoom lens of this embodiment satisfies theconditional expression (3) below, or it is more preferable that the zoomlens of this embodiment satisfies the conditional expression (3-1)below:

0.02<D14/fw<0.3  (3), or

0.09<D14/fw<0.25  (3-1)

where D14 is an interval between the second-group fourth lens and thesecond-group fifth lens along the optical axis, and fw is a focal lengthof the entire lens system at the wide-angle end.

It is preferable that the zoom lens of this embodiment satisfies theconditional expression (4) below, or it is more preferable that the zoomlens of this embodiment satisfies the conditional expression (4-1)below:

0.15<D12/fw<0.6  (4), or

0.20<D12/fw<0.52  (4-1)

where D12 is an interval between the second-group third lens and thesecond-group fourth lens along the optical axis, and fw is a focallength of the entire lens system at the wide-angle end.

In the zoom lens of this embodiment, it is preferable that each of thesecond-group first lens and the second-group fourth lens has anaspherical surface on at least one side thereof.

It is preferable that the zoom lens of this embodiment satisfies theconditional expression (5) below:

ω>38  (5),

where ω is a half angle of view at the wide-angle end.

The imaging apparatus of the invention comprises the above-describedzoom lens of the invention.

According to the zoom lens of the invention, which substantiallyconsists of three lens groups including, in order from the object side,a first lens group having a negative refractive power, a second lensgroup having a positive refractive power and a third lens group having apositive refractive power, wherein, during magnification change from thewide-angle end to the telephoto end, at least the first lens group andthe second lens group are moved along the optical axis such that aninterval between the first lens group and the second lens group isdecreased and an interval between the second lens group and the thirdlens group is increased, configuring the second lens group to consistof, in order from the object side, a second-group first lens having apositive refractive power, a cemented lens consisting of a second-groupsecond lens having a positive refractive power and a second-group thirdlens having a negative refractive power, a second-group fourth lenshaving a positive refractive power and a second-group fifth lens havinga negative refractive power allows achieving a wide-angle zoom lenshaving high optical performance for achieving a small F-number andreduction of the entire length of the zoom lens. As a result, a zoomlens that can achieve an image size lager than a conventional image sizerelative to the entire length of the zoom lens can be provided whileachieving reduction of the entire length of the zoom lens.

According to the zoom lens of the invention, when the conditionalexpression (1) is satisfied, the power of the second group can besuccessfully maintained, and reduction of the entire length of the zoomlens and a small F-number can be achieved. Further, when the zoom lensof the invention satisfies the conditional expression (1-1), a moreremarkable level of the above-described effects can be obtained.

Further, in the case where the zoom lens of the invention satisfies theconditional expression (2), minimization of the field curvature canpreferably be achieved. Further, when the zoom lens of the inventionsatisfies the conditional expression (2-1), a more remarkable level ofthe above-described effect can be obtained.

Further, in the case where each of the second-group first lens and thesecond-group fourth lens has an aspherical surface on at least one sidethereof, the second-group first lens having an aspherical surface on atleast one side thereof allows, in particular, more preferably correctingspherical aberration, and the second-group fourth lens having anaspherical surface on at least one side thereof allows, in particular,more preferably correcting astigmatism.

Further, in the invention, in the case where the conditional expression(3) is satisfied, the power of the second lens group is preferablymaintained, thereby allowing reduction of the entire length of the zoomlens and reduction of the collapsed thickness of the zoom lens whileachieving successful correction of astigmatism. Further, in theinvention, in the case where the conditional expression (3-1) issatisfied, a more remarkable level of the above-described effects can beobtained. In the invention, in the case where the conditional expression(4) is satisfied, the power of the second lens group is preferablymaintained, thereby allowing reduction of the entire length of the zoomlens and reduction of the thickness of the zoom lens when it isretracted (the collapsed thickness) while achieving successfulcorrection of astigmatism. Further, in the invention, in the case wherethe conditional expression (4-1) is satisfied, a more remarkable levelof the above-described effects can be obtained. In the invention, in thecase where the conditional expression (5) is satisfied, wide-angleimaging can preferably be performed.

According to the imaging apparatus of the invention, which is providedwith the above-described high-performance zoom lens of the invention,the entire apparatus can be made compact, and a photographed image withhigher image quality can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating the lens configuration of a zoomlens according to Example 1 of the invention,

FIG. 2 is a sectional view illustrating the lens configuration of a zoomlens according to Example 2 of the invention,

FIG. 3 is a sectional view illustrating the lens configuration of a zoomlens according to Example 3 of the invention,

FIG. 4 is a sectional view illustrating the lens configuration of a zoomlens according to Example 4 of the invention,

FIG. 5 is a sectional view illustrating the lens configuration of a zoomlens according to Example 5 of the invention,

FIG. 6 is a sectional view illustrating the lens configuration of a zoomlens according to Example 6 of the invention,

FIG. 7 is a sectional view illustrating the lens configuration of a zoomlens according to Example 7 of the invention,

FIG. 8 is a sectional view illustrating the lens configuration of a zoomlens according to Example 8 of the invention,

FIG. 9 is a sectional view illustrating the lens configuration of a zoomlens according to Example 9 of the invention,

FIG. 10 is a sectional view illustrating the lens configuration of azoom lens according to Example 10 of the invention,

FIG. 11 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 1 of the invention,

FIG. 12 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 2 of the invention,

FIG. 13 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 3 of the invention,

FIG. 14 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 4 of the invention,

FIG. 15 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 5 of the invention,

FIG. 16 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 6 of the invention,

FIG. 17 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 7 of the invention,

FIG. 18 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 8 of the invention,

FIG. 19 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 9 of the invention,

FIG. 20 shows, at “A” to “L”, aberration diagrams of the zoom lensaccording to Example 10 of the invention,

FIG. 21A is a front perspective view of an imaging apparatus accordingto an embodiment of the invention, and

FIG. 21B is a rear perspective view of the imaging apparatus accordingto the embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described indetail with reference to the drawings.

FIG. 1 is a sectional view illustrating the configuration of a zoom lensaccording to one embodiment of the invention, and corresponds to a zoomlens of Example 1, which will be described later. FIGS. 2 to 10 aresectional views illustrating the configurations of zoom lenses ofExamples 2 to 10, respectively, which will be described later. The zoomlenses shown in FIGS. 1 to 10 have the same basic configuration and areshown in the drawings in the same manner. Therefore, in the followingdescription, the zoom lens shown in FIG. 1 is mainly explained as anexample.

In FIG. 1, the left side is referred to as “object side” and the rightside is referred to as “image side”. In FIG. 1, an arrangement of lensesat the wide-angle end when the focus is set to infinity is shown at thetop, an arrangement of lenses at an intermediate position when the focusis set to infinity is shown at the middle, and an arrangement of lensesat the telephoto end when the focus is set to infinity is shown at thebottom. Schematic trajectories of lens groups during magnificationchange are shown by the solid lines drawn between the top and the middleand between the middle and the bottom.

The zoom lens shown in FIG. 1 substantially consists of three lensgroups, which includes, in order from the object side along an opticalaxis Z, a first lens group G1 having a negative refractive power, asecond lens group G2 having a positive refractive power and a third lensgroup G3 having a positive refractive power, where, during magnificationchange from the wide-angle end to the telephoto end, at least the firstlens group G1 and the second lens group G2 are moved along the opticalaxis Z such that the interval between the first lens group G1 and thesecond lens group G2 is decreased and the interval between the secondlens group and the third lens group G3 is increased. That is, in thiszoom lens, the interval between the first lens group G1 and the secondlens group G2 and the interval between the second lens group G2 and thethird lens group G3 are changed during magnification change from thewide-angle end to the telephoto end. Further, an aperture stop St isdisposed between the first lens group G1 and the second lens group G2.

For example, in the zoom lens of the example shown in FIG. 1, the lensgroups are moved along the trajectories shown by the arrows in thedrawing during magnification change from the wide-angle end to thetelephoto end. Also, the interval between the third lens group G3 andthe imaging plane 100 is changed during the magnification change. Itshould be noted that, in the zoom lens of the example shown in FIG. 1,the aperture stop St is configured to be moved together with the secondlens group G2 during the magnification change.

The aperture stop St shown in FIG. 1 does not necessarily represents thesize and the shape thereof, but represents the position thereof alongthe optical axis Z.

When the zoom lens is applied to an imaging apparatus, it is preferablethat a glass cover, filters, such as an infrared cut filter and alow-pass filter, etc., are provided between the most image-side lens andthe imaging plane (imaging surface) 100 depending on the configurationof a camera on which the lens is mounted. In the example shown in FIG.1, a parallel plate-like optical member PP that is assumed to representthe above-mentioned elements is disposed on the image side of the thirdlens group G3.

It should be noted that, in the example shown in FIG. 1, when this zoomlens is applied to an imaging apparatus, for example, the zoom lens isdisposed such that the imaging surface of the image sensor is positionedin the imaging plane 100.

Now, the configuration of each lens group of the zoom lens shown in FIG.1 is described in detail.

The first lens group G1 as a whole has a negative refractive power. Inthis example, the first lens group G1 includes, in order from the objectside, a first-group first lens L11 which is a meniscus lens having anegative refractive power with the convex surface facing the objectside, a first-group second lens L12 which is a meniscus lens having anegative refractive power with the convex surface facing the objectside, and a first-group third lens L13 having a positive refractivepower with the convex surface facing the object side. In this example,the first-group third lens L13 have aspherical surfaces on both sidesthereof.

The second lens group G2 as a whole has a positive refractive power. Thesecond lens group G2 includes, in order from the object side, asecond-group first lens L21 having a positive refractive power, acemented lens formed by a second-group second lens L22 having a positiverefractive power and a second-group third lens having a negativerefractive power L23, a second-group fourth lens L24 having a positiverefractive power, and a second-group fifth lens L25 having a negativerefractive power. In the second lens group G2, it is preferable that atleast one surface of each of the second-group first lens L21 and thesecond-group fourth lens L24 is an aspherical surface lens. In thisexample, each of the second-group first lens L21 and the second-groupfourth lens L24 has aspherical surfaces on both sides thereof.

The third lens group G3 as a whole has a positive refractive power. Thethird lens group G3 includes a third-group first lens L31 having apositive refractive power.

This zoom lens is adapted to satisfy the conditional expressions (1) and(2) below:

−0.9<fw/f25<0  (1) and

−0.40<(R15+R16)/(R15−R16)<2.40  (2),

where fw is a focal length of the entire lens system at the wide-angleend, f25 is a focal length of the second-group fifth lens, R15 is aparaxial radius of curvature of the object-side surface of thesecond-group fifth lens, and R16 is a paraxial radius of curvature ofthe image-side surface of the second-group fifth lens.

It is preferable that this zoom lens further satisfies the conditionalexpressions (3) to (5) below:

0.02<D14/fw<0.3  (3),

0.15<D12/fw<0.6  (4) and

ω>38  (5),

where D14 is an interval between the second-group fourth lens and thesecond-group fifth lens along the optical axis, D12 is an intervalbetween the second-group third lens and the second-group fourth lensalong the optical axis, fw is a focal length of the entire lens systemat the wide-angle end, and w is a half angle of view at the wide-angleend. As preferred aspects, the zoom lens may satisfy any one or anycombination of the conditional expressions (3) to (5).

In this zoom lens, as a material disposed on the most object side,specifically, it is preferable to use glass. Alternatively, atransparent ceramic may be used.

As a material forming a lens with an aspherical surface, glass may beused, or a plastic can also be used. In a case where a plastic is used,weight reduction and cost reduction can be achieved.

It is preferable that the zoom lens is provided with a multi-layerprotective coating. Besides the protective coating, the zoom lens may beprovided with an anti-reflection coating film for reducing ghost light,etc., during use.

In the example shown in FIG. 1, the optical member PP is disposedbetween the lens system and the imaging plane. However, the variousfilters, such as a lowpass filter and a filter that cuts off a specificwavelength range, etc., may be disposed between the lenses, or, in placeof disposing the various filters, coatings having the same functions asthe various filters may be applied to the lens surfaces of some of thelenses.

The aperture stop St may be disposed at any position between the mostimage-side surface in the first lens group and the most image-sidesurface in the second lens group, and whether or not the aperture stopSt is moved is not limited to that in the above-described example. Forexample, the aperture stop may be fixed during magnification change ormay be moved separately from the lens groups during magnificationchange.

Operation and effect of the zoom lens having the above-describedconfiguration is described.

As described above, the zoom lens shown in FIG. 1 includes, in orderfrom the object side, the first to third lens groups that are negative,positive and positive lens groups, wherein, during magnification changefrom the wide-angle end to the telephoto end, an interval between thelens groups is changed such that at least the first lens group and thesecond lens group are moved along the optical axis and an intervalbetween the first lens group and the second lens group is decreased andan interval between the second lens group and the third lens group isincreased, and the second lens group includes, in order from the objectside, the second-group first lens having a positive refractive power,the cemented lens formed by the second-group second lens having apositive refractive power and the second-group third lens having anegative refractive power, the second-group fourth lens having apositive refractive power, and the second-group fifth lens having anegative refractive power. This configuration allows providing awide-angle zoom lens having high optical performance for achieving asmall F-number and reduction of the entire length of the zoom lens. Inparticular, the second lens group G2 having the five-lens configurationpreferably allows achieving a small F-number, and the second-group fifthlens L25 having a negative refractive power lens preferably allowsachieving the reduction of the entire length of the lens system. Incontrast, the zoom lenses of Patent Documents 1 and 2, for example, havea large F-number at the wide-angle end.

Further, according to the above-described configuration, the power ofeach lens group can be optimized. This allows achieving a zoom lens thatcan accommodate an image size, such as a ⅔-inch type image size, largerthan a conventional image size, while achieving the reduction of theentire length of the zoom lens. With this, a demand in development forapplying a larger size image sensor to provide higher image quality of adigital camera, or the like, can be met. In contrast, the zoom lensdisclosed in Patent Document 3, for example, has an excessively longentire length of the zoom lens relative to the image size, and cannotachieve an image size corresponding to a large image sensor, such as a⅔-inch type image sensor, while maintaining a compact entire length ofthe zoom lens.

The configuration of the first lens group G1 including the first-groupfirst lens L11 which is a meniscus lens having a negative refractivepower with the convex surface facing the object side, the first-groupsecond lens L12 which is a meniscus lens having a negative refractivepower with the convex surface facing the object side and the first-groupthird lens L13 having a positive refractive power with the convexsurface facing the object side allows reducing the thickness (length inthe optical axis direction) of the first lens group G1 and achievingreduction of the entire length of the zoom lens. The first-group thirdlens L13 having an aspherical surface at least on one side thereofallows successful correction of astigmatism across the entire zoom rangeand distortion at the wide-angle end. Further, in the zoom lens shown inFIG. 1, the first-group third lens L13 has aspherical surfaces on bothsides thereof. This more preferably allows correcting the astigmatismacross the entire zoom range and the distortion at the wide-angle end.

In the second lens group G2, the second-group second lens L22 having apositive refractive power and the second-group third lens L23 having anegative refractive power are cemented together to form the cementedlens, thereby making the interval between the second-group second lensL22 and the second-group third lens L23 almost zero. This allowsminimizing occurrence of the “half blur” problem, where good focusingcharacteristics cannot be obtained at a part of a photographed image dueto the second-group second lens L22 and the second-group third lens L23being eccentrically disposed at positions out of intended positionsthereof. In addition, in the case where the second-group second lens L22and the second-group third lens L23 are cemented together to form thecemented lens, the maximum limit of size and the minimum limit of sizeto be met is those of the cemented lens, which is the total of thesecond-group second lens L22 and the second-group third lens L23, andthis facilitates quality control in production. In contrast, in a casewhere the second-group second lens L22 and the second-group third lensL23 are not cemented together, it is necessary to produce each lens suchthat the maximum limit of size and the minimum limit of size of eachlens are individually met.

Further, in the case where each of the second-group first lens and thesecond-group fourth lens has an aspherical surface on at least one sidethereof, the second-group first lens having an aspherical surface on atleast one side thereof allows, in particular, more preferably correctingspherical aberration, and the second-group fourth lens having anaspherical surface on at least one side thereof allows, in particular,more preferably correcting astigmatism. In FIG. 1, each of thesecond-group first lens and the second-group fourth lens has asphericalsurfaces on both sides thereof, and therefore correction of thespherical aberration and the astigmatism can be more preferablyachieved.

The third lens group G3 having a one-lens configuration can preferablycontribute to reduction of the entire length of the zoom lens. Inaddition, by minimizing the number of lens forming the third lens groupG3, cost reduction can be achieved.

The conditional expression (1) defines a preferable range of the ratioof the focal length fw of the entire zoom lens at the wide-angle end tothe focal length f25 of the second-group fifth lens L25. If the lowerlimit of the conditional expression (1) is not reached, the power of thesecond-group fifth lens L25 tends to be strong and the power of thesecond lens group G2 tends to be weak, and it is difficult to achieve alens configuration that can provide a small F-number. In order toachieve a small F-number, one may consider increasing the length(thickness) of the second-group fifth lens L25 along the optical axis.However, this is likely to result in increase of the entire length ofthe zoom lens and therefore is not preferable. If it is attempted toachieve a configuration that can provide a small F-number and reductionof the entire length of the zoom lens when the lower limit of theconditional expression (1) is not reached, it is difficult tosufficiently minimize the field curvature. On the other hand, if theupper limit of the conditional expression (1) is exceeded, the power ofthe second-group fifth lens L25 is weak. In this case, it is difficultto correct spherical aberration occurring in the second lens group G2,and correction of astigmatism is not easy. When the second-group fifthlens L25 and the other lens groups are adapted to satisfy theconditional expression (1), successful correction of the fieldcurvature, the spherical aberration and the astigmatism can be achieved,and a small F-number of the zoom lens can be achieved while minimizingincrease of the entire length of the zoom lens. In this view, it ispreferable for providing higher optical performance that the numericalrange for the conditional expression (1) is as follows:

−0.78<fw/f25<−0.14  (1-1).

The conditional expression (2) defines a preferred range of the paraxialradius of curvature R15 on the image side and the paraxial radius ofcurvature R16 on the object side of the second-group fifth lens L25 inthe second lens group G2. If the lower limit of the conditionalexpression (2) is not reached, tendency of a field curvature in the“under” (or negative) direction is high and this is not preferable. Onthe other hand, if the upper limit of the conditional expression (2) isexceeded, tendency of a field curvature in the “over” (or positive)direction is high and this is not preferable. When the paraxial radiusof curvature on the image side and the paraxial radius of curvature onthe object side of the second-group fifth lens L25 are adapted tosatisfy the conditional expression (2), successful minimization of thefield curvature can be achieved. In this view, it is more preferablethat the numerical range for the conditional expression (2) is asfollows:

−0.35<(R15+R16)/(R15−R16)<0.30  (2-1).

The conditional expression (3) defines a preferable range of the ratioof the interval D14 between the second-group fourth lens L24 and thesecond-group fifth lens L25 in the second lens group G2 along theoptical axis to the focal length fw of the entire zoom lens at thewide-angle end. If the lower limit of the conditional expression (3) isnot reached, the power of the second lens group G2 tends to be weak. Inthis case, one may consider increasing the amount of movement of thesecond lens group G2 during magnification change to achieve a sufficientzoom ratio. However, this also results in increase of the entire lengthof the zoom lens to achieve a sufficient zoom ratio, and is thereforenot preferable. On the other hand, if the upper limit of the conditionalexpression (3) is exceeded, the power of the second lens group G2 tendsto be strong. While this is advantageous in view of reduction of theentire length of the zoom lens, this makes it difficult to minimizeastigmatism. Further, the length of the second lens group G2 in theoptical axis direction is increased, and this tends to increase thecollapsed thickness of the zoom lens and is not preferable. When theinterval between the second-group fourth lens L24 and the second-groupfifth lens L25 along the optical axis and the focal length of the entirezoom lens at the wide-angle end are adapted to satisfy the conditionalexpression (3), it is easier to achieve reduction of the entire lengthof the zoom lens and reduction of the collapsed thickness of the zoomlens while preferably maintaining the power of the second lens group,and it is easier to correct astigmatism. In this view, it is preferablefor providing higher optical performance that the numerical range forthe conditional expression (3) is as follows:

0.09<D14/fw<0.25  (3-1).

The conditional expression (4) defines a preferable range of the ratioof the interval D12 between the second-group third lens L23 and thesecond-group fourth lens L24 in the second lens group G2 along theoptical axis to the focal length fw of the entire zoom lens at thewide-angle end. If the lower limit of the conditional expression (4) isnot reached, the power of the second lens group G2 tends to be weak. Inthis case, one may consider increasing the amount of movement of thesecond lens group G2 during magnification change to achieve a sufficientzoom ratio. However, this results in increase of the entire length ofthe zoom lens to achieve a sufficient zoom ratio, and is therefore notpreferable. On the other hand, if the upper limit of the conditionalexpression (4) is exceeded, the power of the second lens group G2 tendsto be strong. While this is advantageous in view of reduction of theentire lens length, this makes it difficult to minimize astigmatism.Further, the length of the second lens group G2 in the optical axisdirection is increased, and this tends to increase the collapsedthickness of the zoom lens and is not preferable. When the intervalbetween the second-group third lens L23 and the second-group fourth lensL24 along the optical axis and the focal length of the entire zoom lensat the wide-angle end are adapted to satisfy the conditional expression(4), it is easier to achieve reduction of the entire length of the zoomlens and reduction of the collapsed thickness of the zoom lens whilepreferably maintaining the power of the second lens group, and it iseasier to correct astigmatism. In this view, it is preferable forproviding higher optical performance that the numerical range for theconditional expression (4) is as follows:

0.20<D12/fw<0.52  (4-1).

The conditional expression (5) defines a preferable range of the halfangle of view ω at the wide-angle end. If the lower limit of theconditional expression (5) is not reached, it is difficult to performwide-angle imaging. When the conditional expression (5) is satisfied, azoom lens that allows wide-angle imaging can be achieved.

As described above, according to the zoom lens of this embodiment, awide-angle zoom lens having high optical performance for achieving asmall F-number and reduction of the entire length of the zoom lens canbe achieved by optimizing the lens configuration of the zoom lens havinga three-group configuration to satisfy the appropriate conditionalexpressions, as necessary. As a result, a zoom lens that can achieve animage size larger than a conventional image size relative to the entirelength of the zoom lens can be provided while achieving reduction of theentire length of the zoom lens. Further, according to an imagingapparatus provided with the zoom lens according to this embodiment, theentire apparatus can be made compact while maintaining good imagingperformance that allows wide-angle imaging.

Next, numerical examples of the zoom lens of the invention aredescribed. FIGS. 1 to 10 show sectional views of zoom lenses of Examples1 to 10, respectively.

Tables 1 to 3, which are presented below, show specific lens datacorresponding to the configuration of the zoom lens shown in FIG. 1.Specifically, Table 1 shows lens data, Table 2 shows data of asphericalsurfaces, and Table 3 shows data with respect to magnification changeand specification data of the zoom lens of Example 1. Similarly, thelens data, the data of aspherical surfaces and the data with respect tomagnification change of the zoom lenses of Examples 2 to 10 are shown inTables 4 to 30. In the following description, meanings of symbols usedin the tables are explained with respect to Example 1 as an example.Basically, the same explanations apply to those with respect to Examples2 to 10.

In the lens data shown in Table 1, each value in the column of “Si”represents the surface number of the i-th (i=1, 2, 3, . . . ) surface,where the surface of the most object-side element is the 1st surface andthe number is sequentially increased toward the image side, each valuein the column of “Ri” represents the radius of curvature of the i-thsurface, and each value in the column of “Di” represents the surfaceinterval between the i-th surface and the i+1-th surface along theoptical axis Z. It should be noted that the value at the bottom in thecolumn of surface interval is a surface interval between the lastsurface shown in the table and the imaging plane. Further, in the lensdata shown in Table 1, each value in the column of “Ndj” represents therefractive index with respect to the d-line (the wavelength of 587.6 nm)of the j-th (j=1, 2, 3, . . . ) optical element, where the mostobject-side lens is the 1st element and the number is sequentiallyincreased toward the image side, and each value in the column of “νdj”represents the Abbe number with respect to the d-line of the j-thelement. It should be noted that the lens data also includes data of theaperture stop St and the optical member PP. The text “(aperture stop)”is shown at the position in the column of the surface number of thesurface corresponding to the aperture stop St. In the lens data, apositive radius of curvature indicates a surface that is convex towardthe object side, and a negative radius of curvature indicates a surfacethat is convex toward the image side.

In the lens data shown in Table 1, the texts “DD[6] (variable)”,“DD[16](variable)”, “DD[18](variable)” and “DD[20](variable)” are shownat positions in the column of surface interval corresponding to theinterval between the first lens group G1 and the second lens group G2,the interval between the second lens group G2 and the aperture stop St,the interval between the second lens group G2 and the third lens groupG3, the interval between the third lens group G3 and the optical memberPP, and the interval between the optical member PP and the imagingplane, which are changed during magnification change. It should be notedthat, with respect to Example 3, only the “DD[6](variable)” and“DD[16](variable)” are variables.

In the lens data shown in Table 1, the symbol “*” is added to thesurface number of each aspherical surface, and a numerical value of theparaxial radius of curvature of the aspherical surface is shown as theradius of curvature. The data of aspherical surfaces shown in Table 2shows the surface number Si of each aspherical surface and asphericalcoefficients of the aspherical surface. The aspherical coefficients arevalues of coefficients KA and Am (where m=3, 4, 5, . . . , 20) in theaspherical surface equation (6) below:

Zd=C·h ²/{(+(1−KA·C ² ·h ²)^(1/2) }+ΣAm·h ^(m)  (6)

where Zd is a depth of the aspherical surface (a length of aperpendicular line from a point with a height h on the asphericalsurface to a plane tangent to the apex of the aspherical surface andperpendicular to the optical axis), h is the height (a distance from theoptical axis to the lens surface), C is a reciprocal of the paraxialcurvature, and KA and Am are aspherical coefficients (where m=3, 4, 5, .. . , 20).

Table 3 shows data with respect to magnification change andspecification data. The data with respect to magnification change shownin Table 3 shows values of the surface intervals DD[6], DD[16], DD[18]and DD[20] at the wide-angle end, at an intermediate position and at thetelephoto end. The specification data shown in Table 3 shows values ofthe zoom magnification (zoom ratio), the focal length f, the backfocusBf (equivalent air distance), the F-number Fno. and the total angle ofview 2ω at the wide-angle end, at the intermediate position and at thetelephoto end.

The unit of Ri and Di shown in Table 1, the unit of f, DD[6], DD[16],DD[18] and DD[20] shown in Table 3, and the unit of Zd and h in theequation (A) may be millimeters. However, since optical systems can beused with being proportionally enlarged or reduced, the unit is notlimited to millimeters and any other suitable unit may be used. The unitof the total angle of view 2ω shown in Table 3 is degrees.

Table 31 shows values corresponding to the conditional expressions (1)to (5) with respect to Examples 1 to 10. As can be seen from Table 31,all of Examples 1 to 10 satisfy the conditional expressions (1) to (5).

FIG. 11 shows, at “A” to “D”, aberration diagrams of sphericalaberration, astigmatism, distortion and lateral aberration (lateralchromatic aberration) of the zoom lens of Example 1 at the wide-angleend. FIG. 11 also shows, at “E” to “H”, aberration diagrams of sphericalaberration, astigmatism, distortion and lateral aberration of the zoomlens of Example 1 at an intermediate position in the zoom range. FIG. 11also shows, at “I” to “L”, aberration diagrams of spherical aberration,astigmatism, distortion and lateral aberration of the zoom lens ofExample 1 at the telephoto end.

The aberration diagrams showing spherical aberration, astigmatism anddistortion show aberrations with respect to the d-line (the wavelengthof 587.6 nm) being the reference wavelength. In each sphericalaberration diagram, aberration with respect to the d-line is shown inthe solid line, aberration with respect to the C-line (656.3 nm) isshown in the dashed line, and aberration with respect to the F-line (thewavelength of 486.1 nm) is shown in the dotted line. In each astigmatismdiagram, aberration in the sagittal direction is shown in the solid lineand aberration in the tangential direction is shown in the dotted line.In each lateral aberration diagram, aberration with respect to theC-line (656.3 nm) is shown in the dashed line, and aberration withrespect to the F-line (the wavelength of 486.1 nm) is shown in thedotted line. The symbol “Fno.” in the spherical aberration diagramsmeans “F-number” and the symbol “ω” in other aberration diagrams mean“half angle of view”.

Similarly, FIG. 12 shows, at “A” to “L”, the aberrations of the zoomlens of Example 2 at the wide-angle end, at the intermediate positionand at the telephoto end; FIG. 13 shows, at “A” to “L”, the aberrationsof the zoom lens of Example 3 at the wide-angle end, at the intermediateposition and at the telephoto end; FIG. 14 shows, at “A” to “L”, theaberrations of the zoom lens of Example 4 at the wide-angle end, at theintermediate position and at the telephoto end; FIG. 15 shows, at “A” to“L”, the aberrations of the zoom lens of Example 5 at the wide-angleend, at the intermediate position and at the telephoto end; FIG. 16shows, at “A” to “L”, the aberrations of the zoom lens of Example 6 atthe wide-angle end, at the intermediate position and at the telephotoend; FIG. 17 shows, at “A” to “L”, the aberrations of the zoom lens ofExample 7 at the wide-angle end, at the intermediate position and at thetelephoto end; FIG. 18 shows, at “A” to “L”, the aberrations of the zoomlens of Example 8 at the wide-angle end, at the intermediate positionand at the telephoto end; FIG. 19 shows, at “A” to “L”, the aberrationsof the zoom lens of Example 9 at the wide-angle end, at the intermediateposition and at the telephoto end; and FIG. 20 shows, at “A” to “L”, theaberrations of the zoom lens of Example 10 at the wide-angle end, at theintermediate position and at the telephoto end.

It can be seen from the above-described data that the zoom lenses ofExamples 1 to 10 are compact and have a high magnification of about3.8×, and have high optical performance for achieving a small F-numberand high image quality.

Next, an embodiment of an imaging apparatus of the invention isdescribed. FIGS. 21A and 21B are a front perspective view and a rearperspective view, respectively, of a digital camera 10, which is oneembodiment of the imaging apparatus of the invention.

As shown in FIG. 21A, the digital camera 10 includes, at the front sideof a camera body 11, a zoom lens 12 according to the embodiment of theinvention, a finder objective window 13 a, and a flashlight emittingunit 14 for emitting flashlight toward the subject. The digital camera10 also includes a shutter button 15, which is disposed at the top sideof the camera body 11, and an image sensor 16, such as a CCD or CMOS,which is disposed in the camera body 11, for capturing an image of thesubject imaged by the zoom lens 12.

Further, as shown in FIG. 21B, a LCD (Liquid Crystal Display) 17 fordisplaying images and various setting screens, a finder observationwindow 13 b, a zoom lever 18 used to change the magnification of thezoom lens 12, and an operation button 19 used to perform varioussettings are disposed at the rear side of the camera body 11. It shouldbe noted that this digital camera 10 is configured such that light fromthe subject guided through the front-side finder objective window 13 acan be viewed through the rear-side finder observation window 13 b.

The zoom lens 12 is disposed such that the optical axis directionthereof coincides with the thickness direction of the camera body 11. Asdescribed above, the zoom lens 12 of this embodiment achieves sufficientreduction of the entire length of the zoom lens. Therefore, the entirelength of the optical system in the optical axis direction when the zoomlens 12 is collapsed or retracted into the camera body 11 is reduced,thereby allowing reduction of the thickness of the digital camera 10.Further, since the zoom lens 12 of this embodiment is a wide angle zoomlens and has high optical performance, the digital camera 10 can performimaging with a wide angle of view and obtain good images.

The present invention has been described with reference to theembodiments and examples. However, the invention is not limited to theabove-described embodiments and examples, and various modifications maybe made to the invention. For example, the values of the radius ofcurvature, the surface interval, the refractive index, the Abbe number,etc., of each lens component are not limited to the values shown in theabove-described numerical examples and may take different values.

Further, in the zoom lens of the invention, lens groups that are movedduring magnification change and directions of the movement thereof arenot limited to those of the above-described example.

Although the above-described embodiment is explained in relation to adigital camera as an example of the imaging apparatus, this is notintended to limit the invention. The present invention is alsoapplicable to other imaging apparatuses, such as a video camera, amonitoring camera, etc.

TABLE 1 Example 1: Basic Lens Data Si Ri Di Ndj νdj 1 49.9991 0.901.882997 40.76 2 10.0000 2.80 3 41.9690 0.75 1.882997 40.76 4 18.67602.94 *5 33.1456 2.30 1.999000 20.48 *6 500.0877 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 2.80 1.693500 53.20 *9 33.1777 0.10 108.8000 3.51 1.496999 81.54 11 69.8497 0.80 1.761821 26.52 12 7.5001 2.50*13 10.1438 1.93 1.803480 40.44 *14 −89.3739 0.68 15 −19.9999 1.001.666800 33.05 16 19.9999 DD[16] (variable) 17 21.4046 2.80 1.49699981.54 18 −40.3769 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20 ∞ DD[20](variable) *aspherical surface

TABLE 2 Example 1: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −5.163491E−05 4.026671E−04 −5.926771E−04 3.980217E−046 0.000000E+00 8.880604E−05 −1.515301E−04 1.360043E−05 2.382303E−05 80.000000E+00 2.249686E−05 1.334507E−05 5.637807E−05 −1.089294E−05 90.000000E+00 4.700616E−06 −2.389262E−05 2.194508E−05 −1.627366E−06 130.000000E+00 −5.347401E−04 7.066569E−04 −3.190578E−04 5.832550E−05 140.000000E+00 −7.325352E−04 1.439323E−03 −8.224069E−04 3.266632E−04 A7 A8A9 A10 A11 5 −1.467574E−04 3.086196E−05 −3.106347E−06 −4.352957E−083.178219E−08 6 −1.219138E−05 2.724143E−06 −3.082541E−07 5.063592E−093.460452E−09 8 −9.633368E−08 1.483604E−07 2.167282E−08 −4.424437E−090.000000E+00 9 −1.223627E−06 4.191255E−08 5.991994E−08 −7.558685E−090.000000E+00 13 1.798156E−05 −8.731877E−06 1.576472E−06 −5.873112E−076.926246E−08 14 −5.456224E−05 −3.978280E−06 4.647479E−06 −1.497945E−062.367317E−07 A12 A13 A14 A15 A16 5 1.421154E−09 −4.114571E−10−8.615419E−11 1.487922E−11 9.066599E−13 6 −9.552202E−11 −6.298783E−11−2.950623E−12 1.711729E−12 1.778010E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13 −3.840837E−09 1.943851E−08−3.955114E−09 6.605872E−10 −7.812392E−10 14 −3.697367E−08 1.016211E−08−3.241904E−09 1.540696E−09 8.727365E−11 A17 A18 A19 A20 5 −2.842210E−131.501067E−14 5.991533E−17 −1.369826E−17 6 −2.508988E−14 1.691468E−15−4.495487E−17 1.351970E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 131.050550E−10 5.662914E−11 −1.555974E−11 1.051132E−12 14 −1.404961E−10−4.414693E−11 2.523396E−11 −2.703669E−12

TABLE 3 DD[6] DD[16] DD[18] DD[20] Wide-angle end 22.92 6.31 2.40 0.99Intermediate 8.59 14.29 2.39 0.99 Telephoto end 1.16 29.74 2.54 0.94Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 3.92 2.0881.45 Intermediate 1.9 14.26 3.91 2.90 43.16 Telephoto end 3.8 27.694.01 4.57 22.51

TABLE 4 Example 2: Basic Lens Data Si Ri Di Ndj νdj 1 49.9991 0.901.882997 40.76 2 10.0000 2.80 3 41.1057 0.75 1.882997 40.76 4 21.00612.90 *5 35.1061 2.30 1.999000 20.48 *6 500.0877 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 2.80 1.693500 53.20 *9 28.5481 0.10 108.8602 3.49 1.496999 81.54 11 61.3282 0.80 1.761821 26.52 12 7.5001 2.50*13 10.0000 2.10 1.803480 40.44 *14 −51.0699 1.00 15 −21.8418 2.101.666800 33.05 16 14.0126 DD[16] (variable) 17 22.6579 3.00 1.49699981.54 18 −29.0103 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20 ∞ DD[20](variable) *aspherical surface

TABLE 5 Example 2: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −4.771373E−05 3.953344E−04 −5.934033E−04 3.980552E−046 0.000000E+00 1.032641E−04 −1.640466E−04 1.452956E−05 2.370796E−05 80.000000E+00 3.294413E−05 5.977955E−06 5.428228E−05 −1.091795E−05 90.000000E+00 2.218157E−05 −2.967680E−05 2.065743E−05 −1.790680E−06 130.000000E+00 −5.541142E−04 6.719499E−04 −3.210310E−04 5.663264E−05 140.000000E+00 −8.002759E−04 1.412713E−03 −8.368308E−04 3.244942E−04 A7 A8A9 A10 A11 5 −1.467712E−04 3.085921E−05 −3.106323E−06 −4.349426E−083.178849E−08 6 −1.221002E−05 2.723156E−06 −3.082047E−07 5.064149E−093.461935E−09 8 −6.890857E−08 1.485898E−07 2.073642E−08 −4.632057E−090.000000E+00 9 −1.221341E−06 4.454892E−08 5.983438E−08 −7.987207E−090.000000E+00 13 1.792719E−05 −8.656577E−06 1.575307E−06 −5.824988E−077.019226E−08 14 −5.442808E−05 −3.713433E−06 4.572299E−06 −1.486348E−062.365432E−07 A12 A13 A14 A15 A16 5 1.421529E−09 −4.114985E−10−8.617054E−11 1.487690E−11 9.063603E−13 6 −9.501727E−11 −6.293120E−11−2.952062E−12 1.711382E−12 1.757414E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13 −3.691880E−09 1.946001E−08−3.955812E−09 6.542847E−10 −7.814079E−10 14 −3.661876E−08 1.025017E−08−3.197869E−09 1.516969E−09 8.848572E−11 A17 A18 A19 A20 5 −2.842123E−131.501486E−14 6.059754E−17 −1.375132E−17 6 −2.514480E−14 1.682783E−15−4.533559E−17 1.593833E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 131.050404E−10 5.665532E−11 −1.555083E−11 1.052161E−12 14 −1.404703E−10−4.413286E−11 2.524433E−11 −2.703600E−12

TABLE 6 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.11 4.13 2.64 1.00Intermediate 8.72 11.85 2.42 1.01 Telephoto end 1.03 26.30 2.64 1.11Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.17 2.0881.26 Intermediate 1.9 14.27 3.96 2.92 43.08 Telephoto end 3.8 27.704.28 4.56 22.60

TABLE 7 Example 3: Basic Lens Data Si Ri Di Ndj νdj 1 49.9991 0.901.882997 40.76 2 10.0000 2.80 3 45.9124 0.75 1.882997 40.76 4 24.71902.90 *5 37.2777 2.30 1.999000 20.48 *6 500.0900 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 3.22 1.693500 53.20 *9 27.4908 0.10 108.8000 3.51 1.496999 81.54 11 164.9650 0.80 1.755199 27.51 12 7.50012.50 *13 10.5095 2.10 1.803480 40.44 *14 −25.1298 1.00 15 −15.1462 2.101.639799 34.46 16 13.0086 DD[16] (variable) 17 19.3591 3.00 1.49699981.54 18 −30.9697 2.36 19 ∞ 0.80 1.516798 64.20 20 ∞ 1.01 *asphericalsurface

TABLE 8 Example 3: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −1.223911E−04 4.509993E−04 −5.995593E−04 3.953330E−046 0.000000E+00 2.968518E−05 −9.664813E−05 −3.206975E−06 2.607485E−05 80.000000E+00 1.200120E−05 1.916518E−05 4.971362E−05 −9.575462E−06 90.000000E+00 9.959434E−05 −1.116779E−04 5.944375E−05 −9.816093E−06 130.000000E+00 3.245928E−04 −3.742852E−04 7.909405E−05 −1.645381E−05 140.000000E+00 1.187693E−04 2.243898E−04 −3.658181E−04 2.184660E−04 A7 A8A9 A10 A11 5 −1.460335E−04 3.085012E−05 −3.114182E−06 −4.395715E−083.183100E−08 6 −1.243751E−05 2.738248E−06 −3.033112E−07 4.672678E−093.362383E−09 8 −6.220404E−07 1.938235E−07 3.919707E−08 −7.230664E−090.000000E+00 9 −1.299571E−06 1.652425E−07 8.663900E−08 −1.341049E−080.000000E+00 13 1.360647E−05 −8.927320E−06 1.873810E−06 −3.372956E−072.935967E−08 14 −5.605468E−05 1.308764E−06 2.106427E−06 −8.290581E−071.855151E−07 A12 A13 A14 A15 A16 5 1.433656E−09 −4.102483E−10−8.623934E−11 1.486088E−11 9.033544E−13 6 −1.037956E−10 −6.224986E−11−2.815452E−12 1.767014E−12 1.917512E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13 −1.741989E−08 2.098660E−08−2.909052E−09 3.653544E−10 −8.458360E−10 14 −3.415128E−08 1.046371E−08−2.215007E−09 6.991128E−10 8.019838E−11 A17 A18 A19 A20 5 −2.841613E−131.502097E−14 6.896173E−17 −1.434721E−17 6 −2.526847E−14 1.495019E−15−5.812704E−17 4.531838E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 131.222701E−10 5.932852E−11 −1.537275E−11 8.793825E−13 14 −1.169960E−10−3.873480E−11 2.592468E−11 −3.093351E−12

TABLE 9 DD[6] DD[16] Wide-angle end 24.02 4.05 Intermediate 8.92 11.42Telephoto end 1.14 25.74 Zoom magnification f Bf FNo. 2ω[°] Wide-angleend 1.0 7.35 3.90 2.08 81.17 Intermediate 1.9 14.26 3.90 2.90 43.05Telephoto end 3.8 27.70 3.90 4.58 22.53

TABLE 10 Example 4: Basic Lens Data Si Ri Di Ndj νdj 1 49.9991 0.901.882997 40.76 2 10.0000 2.80 3 43.3929 0.75 1.882997 40.76 4 20.42242.90 *5 34.3376 2.30 1.999000 20.48 *6 500.0900 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.1569 3.27 1.693500 53.20 *9 34.4780 0.10 108.9142 3.51 1.496999 81.54 11 437.7555 0.80 1.755199 27.51 12 7.50012.50 *13 11.6373 2.10 1.803480 40.44 *14 −27.7758 1.00 15 −12.5000 2.101.639799 34.46 16 25.4281 DD[16] (variable) 17 19.0204 3.00 1.49699981.54 18 −42.9680 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20 ∞ DD[20](variable) *aspherical surface

TABLE 11 Example 4: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −6.769773E−05 4.221945E−04 −5.948532E−04 3.980316E−046 0.000000E+00 8.568059E−05 −1.367565E−04 1.187313E−05 2.386217E−05 80.000000E+00 7.860988E−06 2.287645E−05 5.084931E−05 −1.162954E−05 90.000000E+00 −1.179536E−05 1.052369E−05 1.610352E−05 −2.851143E−06 130.000000E+00 −4.723032E−04 6.841227E−04 −2.969060E−04 5.337929E−05 140.000000E+00 −6.737036E−04 1.325107E−03 −8.140434E−04 3.361891E−04 A7 A8A9 A10 A11 5 −1.467036E−04 3.086195E−05 −3.106557E−06 −4.353447E−083.179244E−08 6 −1.217161E−05 2.732095E−06 −3.081943E−07 4.987234E−093.444731E−09 8 −6.179123E−08 1.711820E−07 2.451230E−08 −5.586473E−090.000000E+00 9 −1.243455E−06 8.070991E−08 6.711727E−08 −9.796315E−090.000000E+00 13 1.848706E−05 −8.530612E−06 1.654082E−06 −5.984603E−076.779229E−08 14 −5.851752E−05 −3.918304E−06 4.572378E−06 −1.297612E−062.099242E−07 A12 A13 A14 A15 A16 5 1.421272E−09 −4.114709E−10−8.618474E−11 1.487502E−11 9.061404E−13 6 −9.628176E−11 −6.298636E−11−2.897558E−12 1.715083E−12 1.829666E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13 −3.229627E−09 1.942134E−08−3.939482E−09 6.906788E−10 −7.856064E−10 14 −4.034372E−08 1.113093E−08−3.089229E−09 1.334705E−09 1.054944E−10 A17 A18 A19 A20 5 −2.841526E−131.502101E−14 6.222625E−17 −1.397337E−17 6 −2.520493E−14 1.666980E−15−4.679850E−17 1.954902E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 131.045905E−10 5.659607E−11 −1.554898E−11 1.051139E−12 14 −1.333482E−10−4.395801E−11 2.532292E−11 −2.779705E−12

TABLE 12 DD[6] DD[16] DD[18] DD[20] Wide-angle end 22.52 4.09 2.78 1.00Intermediate 8.63 12.38 2.38 1.00 Telephoto end 1.08 27.50 2.68 0.99Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.31 2.0881.31 Intermediate 1.9 14.26 3.91 2.93 43.18 Telephoto end 3.8 27.694.20 4.56 22.50

TABLE 13 Example 5: Basic Lens Data Si Ri Di Ndj νdj 1 49.9991 0.901.882997 40.76 2 10.0000 2.80 3 50.2262 0.75 1.882997 40.76 4 25.68432.90 *5 36.9622 2.30 1.999000 20.48 *6 500.0900 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0442 2.81 1.693500 53.20 *9 33.2622 0.10 109.2311 3.51 1.496999 81.54 11 5511.6068 0.80 1.755199 27.51 12 7.50012.50 *13 11.4922 2.10 1.803480 40.44 *14 −28.2018 1.77 15 −13.7091 2.101.639799 34.46 16 17.4215 DD[16] (variable) 17 19.4416 3.00 1.49699981.54 18 −30.8566 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20 ∞ DD[20](variable) *aspherical surface

TABLE 14 Example 5: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −7.729126E−05 4.238795E−04 −5.964529E−04 3.978697E−046 0.000000E+00 7.907085E−05 −1.349976E−04 1.120957E−05 2.370896E−05 80.000000E+00 1.485274E−05 4.236173E−05 5.125213E−05 −1.157940E−05 90.000000E+00 3.244988E−05 3.695009E−05 2.093410E−05 −2.652848E−06 130.000000E+00 −3.649050E−04 7.388665E−04 −2.783499E−04 5.631581E−05 140.000000E+00 −6.072183E−04 1.394629E−03 −7.986422E−04 3.391844E−04 A7 A8A9 A10 A11 5 −1.467010E−04 3.086106E−05 −3.106645E−06 −4.354932E−083.179348E−08 6 −1.219103E−05 2.732019E−06 −3.081120E−07 4.986692E−093.442508E−09 8 −3.383682E−08 1.760367E−07 2.447133E−08 −5.920276E−090.000000E+00 9 −1.266461E−06 7.735228E−08 6.682545E−08 −9.947010E−090.000000E+00 13 1.888330E−05 −8.431566E−06 1.664221E−06 −5.883282E−076.939417E−08 14 −5.838409E−05 −3.842852E−06 4.705422E−06 −1.299430E−062.105373E−07 A12 A13 A14 A15 A16 5 1.421201E−09 −4.114629E−10−8.619152E−11 1.487478E−11 9.060081E−13 6 −9.662667E−11 −6.302682E−11−2.896353E−12 1.715223E−12 1.834079E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13 −3.140228E−09 1.944557E−08−3.938477E−09 6.884232E−10 −7.866847E−10 14 −4.076672E−08 1.112690E−08−3.124790E−09 1.346040E−09 1.064546E−10 A17 A18 A19 A20 5 −2.841455E−131.502011E−14 6.258997E−17 −1.401414E−17 6 −2.520910E−14 1.664660E−15−4.726725E−17 1.957331E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 131.044533E−10 5.659620E−11 −1.553800E−11 1.058243E−12 14 −1.328948E−10−4.399664E−11 2.534565E−11 −2.785081E−12

TABLE 15 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.53 3.14 2.41 1.01Intermediate 8.76 10.39 2.39 1.02 Telephoto end 0.92 24.39 2.72 1.23Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 3.95 2.0881.11 Intermediate 1.9 14.27 3.94 2.92 43.02 Telephoto end 3.8 27.714.48 4.56 22.57

TABLE 16 Example 6: Basic Lens Data Si Ri Di Ndj νdj  1 49.9991 0.901.882997 40.76  2 10.0000 2.80  3 50.4346 0.75 1.882997 40.76  4 24.68852.90 *5 35.9331 2.30 1.999000 20.48 *6 500.0900 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 2.82 1.693500 53.20 *9 49.0177 0.10 109.8571 2.99 1.496999 81.54 11 −303.1914 0.80 1.755199 27.51 12 8.22593.81 *13  12.3559 2.10 1.803480 40.44 *14  −27.5266 1.58 15 −12.50002.10 1.639799 34.46 16 16.0385 DD[16] (variable) 17 17.7762 2.801.496999 81.54 18 −33.6765 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20∞ DD[20] (variable) *aspherical surface

TABLE 17 Example 6: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −8.902583E−05 4.386925E−04 −5.984788E−04 3.981530E−046 0.000000E+00 7.504275E−05 −1.259508E−04 1.138205E−05 2.341926E−05 80.000000E+00 9.812187E−06 4.376042E−05 4.986321E−05 −1.145863E−05 90.000000E+00 2.130276E−05 2.948894E−05 2.065644E−05 −2.785293E−06 13 0.000000E+00 −3.637345E−04 5.863729E−04 −2.885861E−04 5.820874E−05 14 0.000000E+00 −6.128726E−04 1.220690E−03 −8.110108E−04 3.396008E−04 A7 A8A9 A10 A11 5 −1.467236E−04 3.086211E−05 −3.106085E−06 −4.352094E−083.179322E−08 6 −1.215007E−05 2.735356E−06 −3.081325E−07 4.945649E−093.446935E−09 8 2.986808E−08 1.751130E−07 2.311265E−08 −5.188526E−090.000000E+00 9 −1.247753E−06 1.024549E−07 7.042325E−08 −9.943426E−090.000000E+00 13  1.727881E−05 −9.055822E−06 1.778641E−06 −5.763899E−076.472952E−08 14  −5.932846E−05 −5.185373E−06 5.091954E−06 −1.355917E−062.163193E−07 A12 A13 A14 A15 A16 5 1.420566E−09 −4.115741E−10−8.620018E−11 1.487488E−11 9.060872E−13 6 −9.650122E−11 −6.300002E−11−2.905427E−12 1.712254E−12 1.798019E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13  −3.790325E−09 1.950174E−08−3.905273E−09 6.854280E−10 −7.854908E−10 14  −4.234451E−08 1.078330E−08−3.268591E−09 1.450185E−09 1.270630E−10 A17 A18 A19 A20 5 −2.841168E−131.502035E−14 6.261148E−17 −1.402209E−17 6 −2.516737E−14 1.670760E−15−4.598719E−17 1.816725E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 13 1.043832E−10 5.646357E−11 −1.554639E−11 1.062090E−12 14  −1.384768E−10−4.510287E−11 2.514022E−11 −2.698151E−12

TABLE 18 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.28 3.00 2.39 1.00Intermediate 8.68 10.37 2.39 1.00 Telephoto end 0.88 24.63 3.02 1.04Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 3.92 2.0881.13 Intermediate 1.9 14.26 3.92 2.92 43.04 Telephoto end 3.8 27.704.59 4.55 22.56

TABLE 19 Example 7: Basic Lens Data Si Ri Di Ndj νdj  1 49.9991 0.901.882997 40.76  2 10.0000 2.80  3 55.4983 0.75 1.882997 40.76 4 26.93022.90 *5 36.9032 2.30 1.999000 20.48 *6 500.0891 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 3.14 1.693500 53.20 *9 23.6266 0.10 108.8535 3.51 1.496999 81.54 11 272.9422 0.80 1.755199 27.51 12 7.50011.50 *13  10.0639 2.10 1.803480 40.44 *14  −25.9535 1.33 15 −14.16922.10 1.639799 34.46 16 15.3177 DD[16] (variable) 17 22.9091 3.001.496999 81.54 18 −27.0135 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20∞ DD[20] (variable) *aspherical surface

TABLE 20 Example 7: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −8.880494E−05 4.191742E−04 −5.980656E−04 3.980065E−046 0.000000E+00 5.395461E−05 −1.293342E−04 7.344024E−06 2.400661E−05 80.000000E+00 −2.686663E−05 5.862824E−05 4.579417E−05 −1.127586E−05 90.000000E+00 −3.403974E−07 3.278091E−05 2.348761E−05 −3.179042E−06 13 0.000000E+00 −3.416739E−04 7.536647E−04 −2.314772E−04 6.073760E−05 14 0.000000E+00 −5.860723E−04 1.477267E−03 −7.664555E−04 3.482394E−04 A7 A8A9 A10 A11 5 −1.467092E−04 3.086144E−05 −3.106951E−06 −4.356688E−083.178985E−08 6 −1.217333E−05 2.732435E−06 −3.087532E−07 4.898068E−093.437502E−09 8 −2.292738E−08 1.766067E−07 2.140926E−08 −5.933345E−090.000000E+00 9 −1.475978E−06 7.937169E−08 6.735406E−08 −1.063391E−080.000000E+00 13  1.831573E−05 −8.835552E−06 1.821467E−06 −5.659848E−076.686133E−08 14  −5.735767E−05 −4.865904E−06 5.027895E−06 −1.311289E−062.186812E−07 A12 A13 A14 A15 A16 5 1.421394E−09 −4.114879E−10−8.619316E−11 1.487540E−11 9.062263E−13 6 −9.632591E−11 −6.292369E−11−2.870859E−12 1.716390E−12 1.838249E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13  −3.246129E−09 1.961567E−08−3.896251E−09 6.684427E−10 −7.870220E−10 14  −4.070156E−08 1.090813E−08−3.235273E−09 1.355714E−09 1.384744E−10 A17 A18 A19 A20 5 −2.841082E−131.502558E−14 6.253805E−17 −1.420787E−17 6 −2.518243E−14 1.665355E−15−4.792829E−17 1.840309E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 13 1.047004E−10 5.652912E−11 −1.551561E−11 1.062483E−12 14  −1.375026E−10−4.485042E−11 2.518058E−11 −2.705333E−12

TABLE 21 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.57 3.86 2.76 1.01Intermediate 8.94 11.45 2.42 1.02 Telephoto end 0.99 25.34 2.61 1.17Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.30 2.0881.13 Intermediate 1.9 14.27 3.97 2.93 42.98 Telephoto end 3.8 27.704.31 4.56 22.61

TABLE 22 Example 8: Basic Lens Data Si Ri Di Ndj νdj  1 49.9992 0.901.882997 40.76  2 9.8900 3.00  3 42.0138 0.75 1.882997 40.76  4 23.23881.50 *5 32.2414 2.30 1.999000 20.48 *6 500.0000 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 2.80 1.693500 53.20 *9 36.9185 0.10 1010.5441 3.51 1.496999 81.54 11 −505.8144 0.80 1.755199 27.51 12 7.50012.50 *13  10.0000 2.10 1.803480 40.44 *14  −16.9864 1.00 15 −12.49992.10 1.639799 34.46 16 12.4999 DD[16] (variable) 17 21.4038 3.001.496999 81.54 18 −32.2212 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20∞ DD[20] (variable) *aspherical surface

TABLE 23 Example 8: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −6.382439E−05 3.669788E−04 −5.907396E−04 3.943256E−046 0.000000E+00 5.213277E−05 −1.562372E−04 −7.579221E−06 2.593462E−05 80.000000E+00 1.360266E−05 −7.741682E−05 4.785372E−05 −9.476985E−06 90.000000E+00 1.004411E−04 −2.551312E−04 6.591357E−05 −1.544282E−05 13 0.000000E+00 −2.031584E−04 2.364433E−04 −1.097570E−04 −2.128695E−05 14 0.000000E+00 −4.731918E−04 9.204000E−04 −6.784464E−04 2.850763E−04 A7 A8A9 A10 A11 5 −1.463092E−04 3.087464E−05 −3.109580E−06 −4.425403E−083.179330E−08 6 −1.221623E−05 2.706362E−06 −3.098286E−07 4.990384E−093.465693E−09 8 −1.338885E−06 1.393659E−07 9.904295E−08 −1.589882E−080.000000E+00 9 −5.344381E−07 2.368320E−07 4.706385E−08 −1.133290E−080.000000E+00 13  3.253958E−05 −6.533088E−06 −6.822754E−07 9.823759E−08−5.148500E−09 14  −5.295393E−05 −4.375801E−06 6.214158E−06 −2.259302E−064.460657E−07 A12 A13 A14 A15 A16 5 1.425022E−09 −4.103987E−10−8.615759E−11 1.488568E−11 9.040280E−13 6 −9.392980E−11 −6.234680E−11−2.902607E−12 1.711180E−12 1.709075E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13  −2.642447E−09 1.895869E−08−3.923880E−09 7.436064E−10 −7.853486E−10 14  −6.616892E−08 1.101792E−08−1.819677E−09 1.135710E−09 3.242510E−11 A17 A18 A19 A20 5 −2.842447E−131.498793E−14 6.113207E−17 −1.344500E−17 6 −2.529272E−14 1.638010E−15−4.620852E−17 2.349209E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 13 9.433553E−11 5.905906E−11 −1.548256E−11 1.012733E−12 14  −1.226244E−10−4.282060E−11 2.569295E−11 −2.866614E−12

TABLE 24 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.34 2.97 3.27 1.00Intermediate 8.86 10.65 2.80 1.00 Telephoto end 1.07 24.44 2.71 1.02Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.80 2.0881.19 Intermediate 1.9 14.26 4.33 2.90 43.19 Telephoto end 3.8 27.704.26 4.58 22.54

TABLE 25 Example 9: Basic Lens Data Si Ri Di Ndj νdj  1 49.9991 0.901.882997 40.76  2 10.0000 2.80  3 42.1996 0.75 1.882997 40.76  4 23.62342.90 *5 33.0809 2.30 1.999000 20.48 *6 181.3780 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 2.80 1.693500 53.20 *9 28.5226 0.10 108.8000 3.51 1.496999 81.54 11 138.4159 0.80 1.755199 27.51 12 7.51732.50 *13  10.6332 2.10 1.803480 40.44 *14  −20.8262 1.00 15 −12.50002.10 1.639799 34.46 16 13.3451 DD[16] (variable) 17 19.9462 2.801.496999 81.54 18 −29.6215 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20∞ DD[20] (variable) *aspherical surface

TABLE 26 Example 9: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 −1.138684E−04 4.439928E−04 −5.922108E−04 3.935357E−046 0.000000E+00 2.421047E−05 −8.624329E−05 −6.545906E−06 2.753712E−05 80.000000E+00 2.090749E−05 3.126975E−05 6.389773E−05 −1.295898E−05 90.000000E+00 7.594641E−05 −3.135074E−05 5.327775E−05 −5.804090E−06 13 0.000000E+00 −1.927971E−04 3.269027E−04 −1.270587E−04 −9.162797E−06 14 0.000000E+00 −4.589418E−04 1.087397E−03 −8.422803E−04 4.221715E−04 A7 A8A9 A10 A11 5 −1.457318E−04 3.082931E−05 −3.115498E−06 −4.377672E−083.187488E−08 6 −1.253177E−05 2.698098E−06 −2.990376E−07 5.457423E−093.375655E−09 8 −3.048661E−07 2.041907E−07 4.167173E−08 −7.653892E−090.000000E+00 9 −2.240168E−06 1.970489E−07 1.141098E−07 −1.622777E−080.000000E+00 13  3.427919E−05 −1.081819E−05 1.551263E−06 −5.714259E−071.061011E−07 14  −9.038334E−05 −8.322479E−06 9.204119E−06 −2.041751E−062.694997E−07 A12 A13 A14 A15 A16 5 1.433462E−09 −4.101124E−10−8.639091E−11 1.484995E−11 9.016426E−13 6 −1.245242E−10 −6.087427E−11−3.183973E−12 1.823326E−12 1.138021E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13  −1.167058E−08 1.866141E−08−3.841565E−09 8.844524E−10 −8.494566E−10 14  −6.194349E−08 6.660375E−09−1.676628E−09 1.904654E−09 1.987762E−11 A17 A18 A19 A20 5 −2.836251E−131.501401E−14 7.955121E−17 −1.563336E−17 6 −2.456903E−14 1.506931E−15−4.298744E−17 2.473954E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 13 1.068122E−10 5.672977E−11 −1.499225E−11 9.608711E−13 14  −1.374183E−10−4.792050E−11 2.586627E−11 −2.728737E−12

TABLE 27 DD[6] DD[16] DD[18] DD[20] Wide-angle end 23.50 4.03 2.54 1.00Intermediate 8.81 11.50 2.40 1.00 Telephoto end 0.97 25.64 2.78 1.00Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.07 2.0881.18 Intermediate 1.9 14.27 3.93 2.91 43.01 Telephoto end 3.8 27.704.31 4.56 22.57

TABLE 28 Example 10: Basic Lens Data Si Ri Di Ndj νdj  1 49.9991 0.901.882997 40.76  2 10.0000 2.80  3 43.2866 0.75 1.882997 40.76  4 19.98213.23 *5 35.0020 2.30 1.999000 20.48 *6 500.0995 DD[6] (variable) 7(aperture stop) ∞ 0.80 *8 10.0000 3.50 1.693500 53.20 *9 45.4212 0.10 108.8000 3.51 1.496999 81.54 11 −1337.9817 0.80 1.761821 26.52 12 7.50012.50 *13  10.0000 2.10 1.803480 40.44 *14  18.2952 1.00 15 51.6026 2.101.666800 33.05 16 19.9999 DD[16] (variable) 17 29.5958 3.00 1.49699981.54 18 −29.8224 DD[18] (variable) 19 ∞ 0.80 1.516798 64.20 20 ∞ DD[20](variable) *aspherical surface

TABLE 29 Example 10: Data of Aspherical Surfaces Surface No. KA A3 A4 A5A6 5 0.000000E+00 7.093679E−07 3.720843E−04 −5.851393E−04 3.971706E−04 60.000000E+00 1.513155E−04 −1.830000E−04 1.842060E−05 2.519341E−05 80.000000E+00 6.023312E−05 −5.514158E−05 5.999661E−05 −1.034601E−05 90.000000E+00 1.079567E−05 −1.270640E−04 2.090072E−05 −2.252420E−06 13 0.000000E+00 −7.090630E−04 1.916188E−04 −3.512721E−04 2.984603E−05 14 0.000000E+00 −9.329304E−04 9.934464E−04 −8.829851E−04 3.069489E−04 A7 A8A9 A10 A11 5 −1.466694E−04 3.085834E−05 −3.108903E−06 −4.357601E−083.183793E−08 6 −1.250851E−05 2.704787E−06 −3.042242E−07 5.593523E−093.487080E−09 8 −2.960460E−07 1.259118E−07 2.885701E−08 −4.997710E−090.000000E+00 9 −8.232802E−07 4.094091E−08 4.163720E−08 −5.793096E−090.000000E+00 13  1.863679E−05 −6.956251E−06 1.273339E−06 −6.719283E−075.234325E−08 14  −5.427410E−05 −1.474506E−06 3.732139E−06 −1.727907E−062.754966E−07 A12 A13 A14 A15 A16 5 1.428484E−09 −4.111692E−10−8.625131E−11 1.486001E−11 9.038735E−13 6 −1.032312E−10 −6.376949E−11−3.024691E−12 1.720231E−12 1.776593E−14 8 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 9 0.000000E+00 0.000000E+000.000000E+00 0.000000E+00 0.000000E+00 13  −1.748709E−09 2.064290E−08−3.008178E−09 4.990905E−10 −8.009826E−10 14  −1.126520E−08 1.240611E−08−2.013811E−09 3.361846E−10 8.439294E−12 A17 A18 A19 A20 5 −2.841141E−131.506801E−14 7.007030E−17 −1.507409E−17 6 −2.471532E−14 1.695398E−15−4.795425E−17 1.222728E−18 8 0.000000E+00 0.000000E+00 0.000000E+000.000000E+00 9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 13 1.079237E−10 5.586006E−11 −1.576362E−11 1.129441E−12 14  −1.077867E−10−3.460565E−11 2.653862E−11 −3.315731E−12

TABLE 30 DD[6] DD[16] DD[18] DD[20] Wide-angle end 22.65 3.36 2.83 1.00Intermediate 8.64 11.26 2.42 1.00 Telephoto end 1.16 25.71 2.47 1.00Zoom magnification f Bf FNo. 2ω[°] Wide-angle end 1.0 7.35 4.36 2.0881.40 Intermediate 1.9 14.26 3.95 2.94 43.14 Telephoto end 3.8 27.694.00 4.57 22.58

TABLE 31 Expression Conditional Example Example Example Example ExampleExample Example Example Example Example No Expression 1 2 3 4 5 6 7 8 910 (1) fw/25 −0.495 −0.587 −0.691 −0.573 −0.629 −0.688 −0.656 −0.777−0.751 −0.146 (2) (R15 + R16)/ 0.000 0.218 0.076 −0.341 −0.119 −0.124−0.039 0.000 −0.033 2.266 (R15 − R16) (3) D14/fw 0.092 0.136 0.136 0.1360.242 0.215 0.182 0.136 0.136 0.136 (4) D12/fw 0.340 0.340 0.340 0.3400.340 0.519 0.204 0.340 0.340 0.340 (5) ω 40.73 40.63 40.58 40.65 40.5640.56 40.57 40.60 40.59 40.70

What is claimed is:
 1. A zoom lens substantially consisting of threelens groups including, in order from an object side, a first lens grouphaving a negative refractive power, a second lens group having apositive refractive power and a third lens group having a positiverefractive power, wherein, during magnification change from a wide-angleend to a telephoto end, at least the first lens group and the secondlens group are moved along an optical axis such that an interval betweenthe first lens group and the second lens group is decreased and aninterval between the second lens group and the third lens group isincreased, the second lens group consists of, in order from the objectside, a second-group first lens having a positive refractive power, acemented lens consisting of a second-group second lens having a positiverefractive power and a second-group third lens having a negativerefractive power, a second-group fourth lens having a positiverefractive power, and a second-group fifth lens having a negativerefractive power, and the conditional expressions (1) and (2) below aresatisfied:−0.9<fw/f25<0  (1), and−0.40<(R15+R16)/(R15−R16)<2.40  (2), where fw is a focal length of theentire lens system at the wide-angle end, f25 is a focal length of thesecond-group fifth lens, R15 is a paraxial radius of curvature of anobject-side surface of the second-group fifth lens, and R16 is aparaxial radius of curvature of an image-side surface of thesecond-group fifth lens.
 2. The zoom lens as claimed in claim 1, whereinthe conditional expressions (1-1) and (2-1) below are satisfied:−0.78<fw/f25<−0.14  (1-1), and−0.35<(R15+R16)/(R15−R16)<0.30  (2-1).
 3. The zoom lens as claimed inclaim 1, wherein the conditional expression (3) below is satisfied:0.02<D14/fw<0.3  (3), where D14 is an interval between the second-groupfourth lens and the second-group fifth lens along the optical axis. 4.The zoom lens as claimed in claim 3, wherein the conditional expression(3-1) below is satisfied:0.09<D14/fw<0.25  (3-1).
 5. The zoom lens as claimed in claim 1, whereinthe conditional expression (4) below is satisfied:0.15<D12/fw<0.6  (4), where D12 is an interval between the second-groupthird lens and the second-group fourth lens along the optical axis. 6.The zoom lens as claimed in claim 5, where the conditional expression(4-1) below is satisfied:0.20<D12/fw<0.52  (4-1).
 7. The zoom lens as claimed in claim 1, whereineach of the second-group first lens and the second-group fourth lens hasan aspherical surface on at least one side thereof.
 8. The zoom lens asclaimed in claim 1, wherein the conditional expression (5) below issatisfied:ω>38  (5), where ω is a half angle of view at the wide-angle end.
 9. Animaging apparatus comprising the zoom lens as claimed in claim 1.